ACIS Control Circuit: Description
WARNING: This page is about a different car, the 2007 Toyota Camry Solara. However, it is still accessible from the selected car via links, so may be relevant.
HINT:
ACIS stands for "Acoustic Control Induction System".
The ECM opens and closes the Intake Air Control (IAC) valve No. 2 in response to engine speed (RPM/NE). This system improves intake manifold tuning for better efficiency at low and high engine rpm. When the engine speed is 4,000 rpm or less and the throttle valve opening angle is 30° or more, the ECM turns the VSV ON to operate the IAC valve.